1. Field of the Invention
The present invention relates to a communication system using a very small base transceiver station accommodated in a mobile telephone network through an IP (Internet Protocol) network.
2. Description of the Related Art
In a mobile telephone network such as a Third Generation mobile telephone network, there exists an area where radio waves are difficult to penetrate (referred to as “blind zone”) even within a service area (an area in the reach of radio waves from a base transceiver station) on a map. Radio waves basically go straight, which means that radio waves from a base transceiver station may not adequately reach an area such as an area in the shadow of a building, an indoor space, or under the ground.
The blind zone includes, for example, an indoor space, in particular, inside of a personal home such as a detached home or a condominium. It is desired that radio waves from a mobile telephone network be smoothly received in the personal home by installing a very small base transceiver station in the personal home.
Prior arts related to the present invention are disclosed, for example, in Patent Documents 1 and 2 described below.
Patent Document 1: JP 2004-507946 A
Patent Document 2: JP 2002-535888 A